A vehicle mounts a vehicle travel controlling apparatus to alleviate a driving operation of a vehicle by a driver. The vehicle travel controlling apparatus performs an automatic travel control such as a constant-speed travel control, in which a constant vehicle speed (for example, a low vehicle speed of approximately 10 km/h) control is performed so that the vehicle speed of a vehicle is a target vehicle speed, and a follow-up travel control, that is, an adaptive cruise control (ACC) in which the follow-up travel control is performed so that the own vehicle travels to follow the preceding vehicle. In the vehicle travel controlling apparatus, a target driving force as a target control amount is calculated so that the vehicle speed of a vehicle is a target vehicle speed by an automatic travel controlling ECU. In the vehicle travel controlling apparatus, the calculated target driving force is output to an engine ECU, and the engine ECU controls an engine, which serves as a vehicle speed adjusting device that adjusts the vehicle speed of the vehicle, based on the target driving force. For example, the following Patent Literature 1 discloses a technique for performing the automatic travel control of the constant-speed travel.
The following Patent Literature 2 discloses a technique at the time of starting a vehicle on a slope. In this technique, a vehicle braking torque is changed according to the inclination of the slope, whereby the start of the vehicle is supported. The following Patent Literature 3 discloses a technique used when a vehicle traverses a step. In this technique, when it is detected that a vehicle climbs on a step, a driving torque is suppressed, whereby the increase in the vehicle speed is suppressed when the vehicle descends from the step. The following Patent Literature 4 discloses a braking control device. When a master cylinder pressure is more than a wheel cylinder pressure during the automatic braking control, the braking control device releases the automatic braking to switch the control based on the wheel cylinder pressure to the control based on the master cylinder pressure.